The present invention relates to a droplet mist ejection apparatus and particularly a droplet mist ejection apparatus that employs micro electromechanical and piezoelectric techniques and materials to deflect a piezoelectric plate to enable fluid in a casing be pumped and ejected evenly in two directions.
In general, before fuel is channeled into cylinders for combustion, it must be undergone a carburetion or atomizing process to mix with air to become a mixture of a desired proportion to facilitate combustion. However in the design of conventional carburetors, fuel is sucked by air due to Venturi effect and is ejected through fixed nozzles in one direction. Such a design has drawbacks, notably: fuel supply is difficult to control precisely, and atomizing of the fuel in not evenly done and ejection tends to concentrate unevenly.
Some conventional fluid mist ejection apparatus have a piezoelectric plate located in a chamber. A voltage pulse excursion is input to deflect and deform the piezoelectric plate thereby to control flow out pattern and atomization of the fluid in the casing. Such a design may be adopted on general atomizing devices or burners. For instance, U.S. Pat. No. 6,116,517, as shown in FIG. 1A, discloses a droplet mist generator that has a fluid inlet 1 located on one lateral side of a casing 2a and a plural arrays of nozzle orifices 3 located on another side of the casing 2a to form a circulating flow passage. There is a piezoelectric flexural transducer 4 with one end anchored on an inner wall of the casing 2a and another end being a free end. By means of a control unit, the piezoelectric flexural transducer 4 may be deflected and deformed towards the direction of nozzle orifices 3 (as shown in FIG. 1B) to enable the fluid be ejected out through the nozzle orifices 3 in one direction. However, the piezoelectric flexural transducer 4 cannot closely cover the nozzle orifices 3 during deflection, and a fluid ejection differential pressure occurs and the atomization effect and ejection amount are affected. As a result, ejecting efficiency suffers. Moreover, the chamber is relatively large size and is difficult to generate a greater ejection pressure. This also affects the atomization effect. The cited patent also discloses another ejection embodiment as shown in FIG. 2A. It also has an inlet 1 located on one side of the casing 2b and nozzle orifices 3 located on another side of the casing 2b, and a piezoelectric flexural transducer 4 with one end anchored on an inner wall of the casing 2b and another end being a free end. And by means of a control unit, the piezoelectric flexural transducer 4 may be deflected and deformed to close the nozzle orifices 3 extended from the inner wall of the casing 2b (as shown in FIG. 2B). However, the gap between the piezoelectric flexural transducer 4 and the nozzle orifices 3 are not symmetrical or evenly formed. As a result, fluid is not evenly ejected through the gaps. Therefore it can be used only as a constant closed valve, but cannot be used as a pump.
The primary object of the invention is to provide a bi-direction pumping droplet mist ejection apparatus that enables fluid be ejected through nozzle orifices in two directions and to achieve an improved atomization effect.
Further scope of the applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.